Hydraulic motors for pump apparatus



Sept' 1l, 1956 L. P'o'rs HYDRAULIC MOTORS FOR FUMP APPARATUS` 3 Sheets-Sheet 1 Filed June l5 1951 aaa) Emesf L. PCH@ INVENTOR V MM Sept. 1l, 1956 E. l.. PoTTs 2,762,343

HYDRAULIC MOTORS FOR PUMP APPARATUS med June 15, 1951 3 Sheets-Sheet 2 w @new L.v Pons" INVENTOR Sept. 11, 1956 P01-Ts' v762,343 HYDRAUL-IC VMOTORS FOR PUMP APPARATUS 3 `sheetssnaai v:s

Filed June l5, 1951 ATTUH/VEKS United States Patent O HYDRAULIC MOTORS FOR PUMP APPARATUS Ernest L. Potts, Houston, Tex., assgnor to Cicero C. Brown, Houston, Tex.

Application June 15, 1951, Serial No. 231,808

1 Claim. (Cl. 121-164) This invention relates to new and useful improvements in hydraulic motors for pump apparatus.

One object of the invention is to provide an improved high pressure pump apparatus and hydraulic motor therefor which is particularly adaptable for use in building up and maintaining a pressure in a boiler, pipe line or other system, whereby pressure testing of the system under test may be eiliciently accomplished.

An important object of the invention is to provide an improved pump apparatus wherein a relatively low pressure medium may be employed to actuate the apparatus to build up and maintain a desired high pressure in the pressure system under test and also wherein an accurate control of the pressure inthe system under test may be maintained.

A particular object of the invention is to provide an improved hydraulic motor for a pump apparatus which motor includes an improved control valve mechanism which is not exposed to the high pressure in the pressure system under test, whereby the usual D slide valve, together with its inherent disadvantages is eliminated and more etlicient operation with less wear on the valve mechanism is assured.

Still another object is to provide a hydraulic motor having a simplified control valve mechanism for controlling fthe application of the operating pressure iluid to the reciprocating power piston assembly, with said valve meehanism being mounted wholly within the power cylinder, rather than exteriorly thereof.

A further object is to provide a hydraulic motor wherein the control valve mechanism is operated by the power pistons to control the application and exhaust of pressure to the pistons, whereby as the power piston assembly completes its movement in one direction the valve mechanism automatically shifts the direction of application of the power fluid to reverse movement of the power pistons.

A specific object is to provide an improved control valve mechanism in a hydraulic motor wherein the pressure of the operating tluid maintains the valve mechanism in the position to which it is mechanically shifted by engagement of the power pistons therewith; said valve mechanism being constructed to operate with a snap action whereby an instantaneous change of the application of operating lluid to the power pistons is accomplished.

Other objects will appear hereinafter.

The invention will be more readily understood from a reading of the following speciiication and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown, and wherein:

Figure 1 is a longitudinal sectional View of a pump apparatus and hydraulic motor constructed in accordance with the invention and illustrating the power pistons at one limit of their respective strokes.

Figure 2 is a similar view with the power pistons at the opposite limit of their strokes,

line 3 3 of Figure l,

2,762,343 Patented-Sept. 11, 1.95.6

Figure 4 is a transverse sectional view taken on the line 4 4 of Figure 1, j',

Figure 5 is a transverse sectional view taken on the line 5 5 of Figure l,

Figure 6 is a transverse sectional line 6 6 of Figure l,

Figure 7 is a schematic view of the assembly,

Figure 8 is a longitudinal sectional view of -a modied form of the invention,

VFigure 9 is a transverse sectional view takenon the ,line 9 9 of Figure 8, Vand Figure 10 is a schematic view of the modilication shown in Figures 8 and 9. l l

'In the drawings the numeral lldesignates a main fpower cylinder having a bore 11 Within which power pistons A and B are reciprocable. The cylinder 10 has one end `closed by an end plate 12 while its opposite end is closed by a similar plate 1 3. The `pistons A and Bare connected to each other by a connecting rod or :shaft 14 y.whereby said pistons reciprocate as a unit within the cylinder Y10.

A piston rod 15 has connection with the power piston B `and extends outwardly through an axial .opening'16 in the end plate 13; a suitable stutlng box or packing '17 seals ott around the piston rod or plunger 15. The outer end of the piston rod extends through a stumg box or packing 18 in one end of a pump cylinder 19. The cylinder Ahas its end connected in blocks 20 and '21 which may secured to the end plate 13 vby elongate supporting rods 22. The piston -rod 15 yhas Aconnection with vapump plunger 24 which is adapted to reciprocate within the cylinder 19 and the pump piston has a `guide rod 25 which extends `axially through the cylinder and hasV its free end slidable within a suitable stuing box or packing 26. VIt will be evident `that as the power pistons A and B reciprocate within the main power cylinder 1t) a reciprocationis imparted to the pump -pi'ston 24 within 'its cylinder 19 and* the 1latter-is arranged -to be connected with the particular lpressure system, such Aas a boiler, pipe line or the like, which is to be tested. p

The end block or head 20 (Figure 5)v of the pump cylinder 19 is formed with an inlet passage 27"wl1'ich 'is connected to an inlet line 28. The passage 27 has a-lateral extension 27a communicatng with the outer end yof the cylinder 19 and a suitable `spring-pressed check valve 29 is mounted between the inlet 27 and the lateral extension 27a. Upon the movement of the pump pistonj24 in a direction -to the left in Figure 1,'-uid is drawn into ,the cylinder 19 through the inlet 27.A At this time an exhaust passage 30, also formed in the block 20 andrhavingconnection with an exhaust line 31, is closed by a springpressed check 32. Upon reverse movement o f the piston 24, a check valve 29 is closed and valve 32 is opened to expel the uid from the cylinder to the exhaust line. Q

In order that the piston 24 may be double acting, the head 21 is also formed with an inlet passage 127 having a lateral extension 127a communicating with the cylinder 19 and a check valve 129 is mounted in this'inlet passage. An inlet line 128 connects with the inlet 127. An exhaust passage 130 connected with an exhaust line 131 has a check valve 132 disposed therein. lt will be` understood that the inlets 28 and 128 may .be connected tothe same source of fluid while the outlets or exhaust lines 31 .and 131 are connected with the particular system which is to be tested.

With the arrangement of an inlet and Aexhaust in each end of the cylinder 19, it will be apparent `that the piston 24 is double acting, that is, it functions fto provide ,a power stroke in bothdirections. l-

For imparting a reciprocating movement to the pump piston or plunger 24 by means .ofthepower pistons Aand B, the power cylinder is formed with an operating lluid view taken on the Vinlet port 33 to which is connected an operating pressure supply line 34. The inner end of the inlet'port 33 communicates with the bore a of the cylinder and immediately adjacent the port is an elongate passage 35 wherethe operating pressure lluid may be conducted through this passage to that end of the power cylinder which is adjacent the closure plate `1Z. Extending longitudinally in the opposite direction from the inlet port 33 is a similar passage 36 which establishes communication,under certain conditions, between the inlet port 33` and that end of the power cylinder adjacent the closure plate 13. For controlling the ow of the operating pressure fluid to either the passage 35 or the passage 36, an annular valve element C is mounted within the bore 11 of the power cylinder. As is clearly shown in `Figurey l, the valve element includes an annular ring portion 37 having annular anges 38 and 39 thereon and the peripheral edges of the-iianges engage the bore 11 of the cylinder. The valve element is carried by spider arms 37a secured to a collar 37b which is slidable upon the connecting rod 14 which connects the two power pistons A and B. YThe spacing between the flanges 38 and 39 is such that when the element C is in the position shown in Figure 1 a communication between the inlet port 33 and the passage 35 is established; at the same time the ilange 39 shuts off flow between the inlet port 33 and` the passage 36. Shifting of the Valve member C to the position of Figure 2 causes flange 38 of the element to move between the passage 35 and the inlet port to shut ott communication therebetween and at the same time iiange 39 moves beyond the end of the passage 36 to set up a communication between the inlet 33 and passage 36. It is thus evident that as the valve element C is shifted from one position to another, the operating pressure fluid is directed to either one end or the other of the power cylinder.

For fr-ictionally maintaining the valve element in its two positions, as shown in Figures 1 and 2, a pair of diametrically disposed spring-pressed pawls or detents 40 are mounted in the wall of the power cylinder and extend inwardly into the annular chanel 41 which is formed between the flanges 38 and 39 of the valve element C. When the valve element is in the position shown in Figure 1, the spring-pressed detents are engaged within an annular groove 42 provided in the base portion 37 of the element to frictionally lock the element in position. When the element is shifted to the position ofV Figure 2, which shifting is possible b y overcoming the frictional resistance of the detents 40, said detents engage within a second annular groove 43 provided in the base portion 37 of the valveelement. j

For shifting the valve element C from one position (Figure 1) to its other position (Figure 2) with a snap action a pair of coil springs 44 and 45 surround the connecting rod 14 of the power piston assembly. The spring 44 is confined on the rod between the spider collar 37b and the power piston A while the spring 45 surrounds the rodl between the spider collar 37b and the power piston B. The strength of these springs is predetermined so that when saidA spring is compressed a predetermined amount it will exert a predetermined force in expanding. Exhaust of the uid from the power cylinder is effected through a passage 45 which connects with an exhaust line 46.

In the operation of the device with the parts in the position shown in Figure 1, the power pistons A and B have moved to the limit of their travel toward the left in this ligure.. The valve element C has just shifted to the position shown in Figure l and operating pressure is conducted through the inlet 33 and passage 35 to that end of thepower cylinder 10 adjacent the closure plate 12. This pressure uid acting upon the piston A will move the power pistons A and B in a direction to the right in Figure l, and as this movement occurs the pump plunger or piston 24 is reciprocated within its cylinder 19. The piston AV is provided with contact pins 47 which extend outwardly from the inner face of the piston and as piston A moves to the right these contact pins move toward the valve element C. During movement of the assembly to the right in Figure l, fluid is exhausted from that end of the power cylinder adjacent the closure plate 13 through the passage 36 into the area between pistons A and B and then through outlet or exhaust passage 45 to the exhaust line; fluid in advance of the piston A is, of course, also exhausted at the same time through passage 4S.

Prior to the time that the contact pins 47 of piston A engage the liange 38 of the valve member C the piston A engages the end of the spring 44, and this causes the spring 44 to be compressed a predetermined amount before the contact pins 47 engage the valve element. Upon engagement of the pins 47 of the piston A with the valve element, the spring 44 is almost fully compressed and as soon as the piston A imparts sutlicient movement to the valve element to disengage the detents 40 from the groove 42, the action of the Spring 44 against the spider collar 37b causes a rapid and sudden movement of the valve element. Thissudden shifting movement of the valve element is halted by the entry of the detents 40 into the second annular groove 43 of the valve element to halt the movement of the valve element in the position shown in Figure 2.

This shifting of the valve element C directs operating tiuid through passage 36 to that end of the piston adja cent the closure plate 13 and thus, operating uid pressure is applied against piston B to start movement in an opposite direction, that is, in a direction to the left in Figure 2. As the power pistons A and B move to the left in Figure 2, Huid in advance of the piston A is by-passed around the piston through passage 35 into the area between the pistons, and this area between the pistons is exhausted through passage 45 and exhaust line 46. Movement of the pistons A and B in a direction to the left in Figure 2 continues until Contact pins 48 on piston B engage the flange 39 of the valve element C. By this time the spring 45 has been compressed and as soon as fric-l tional engagement of the detents 40 is overcome by the application of direct pressure by piston B, the valve C is rapidly snapped or shifted back to the position shown in Figure l. Such shifting results in a reversal of the application of power fluid to the piston assembly and the pistons A and B again move back in a direction to the right in Figure 1.

It will be evident that the shift in application of power uid is substantially instantaneous and such shift is accomplished by the power pistons as each completes its stroke. As the power pistons reciprocate within the power cylinder 10 the pump piston or plunger 24 is reciprocated to build up the pressure in a system being tested or to perform any desired pumping operation.

In Figures 8 and 9 a modified form of the invention is illustrated wherein a valve assembly D is substituted for the valve element C. In this modification a central partition 50 is connected in the central portion of the power cylinder 10 and has the connecting rod 14 of the pistons A and B slidable therethrough. The valve assembly D is mounted within the partition 50 and includes a valve head 51 and a valve head 52, which valve heads are connected together by a tubular sleeve 53. The valve head 51 is adapted to engage either a valve seat 54 or a valve seat 55, while the valve head 52 is adapted to engage either a valve seat 56 or a valve seat 57. With the valve heads in the position shown in Figure 8, in which case the valve heads are shifted to a position to the left in this iigure, the valve head 51 is in engagement with the seat 55 and is spaced from the seat 54 whereby communication is established between the inlet 33 and the passage 35 so as to conduct operating pressure to that end of the power cylinder adjacent the closure plate 12. At this time the other valve head 52 is engaged with seat 56 and is disengaged from seat 57 whereby communication between the inlet 33 and the passage 36 which leads to that end of the piston adjacent plate 13 is shut olf; at the same time, the spacing of valve head 52 from the seat 57 establishes communication between the passage 36 and the area between piston B and the partition 50. Thus, the operating pressure fluid from the inlet 33 may ow through the passage 35 to act 'against the piston A to move the power piston assembly in a direction to the right in Figure 8. As the pistons A and B move to the right in Figure 8 the iluid between the piston A and partition 50 is discharged directly through the exhaust passage 45 while the fluid between the piston B and the closure plate 13 is discharged through passage 36, past the valve seat 57 into the area between the partition 50 and piston B and nally out through the exhaust passage 45. It is noted that at this time the operating pressure uid is acting against the entire cross-sectional area of the valve head 51 while it is acting only against that portion of valve head 52 which is exposed in the valve seat 56. Therefore, there is an 11n-balance of pressure across the valve heads which holds the valve heads in the position shown in Figure 8.

For effecting a shift of the valve assembly, an operating rod 58 extends axially through the tubular sleeve 53 which connects the valve heads. One end of the rod has a disc 59 secured thereto and a coil spring 60 is confined between the disc and the valve head 51. The opposite end of the rod is provided with a similar. disc 61 and a coil spring 62 is confined between this disc and the opposite valve head 52.

With the parts in the position shown in Figure 8 and with operating pressure being directed against the piston A to move the assembly to a direction to the right in this figure the piston A moves into contact with the disc 59 of the operating rod 58 as said piston approaches the end of its stroke. The coil spring 60 is thereby compressed and is continued to be compressed until the disc 59 strikes the end of an annular extension 51a formed on the valve head 51 and thereafter direct pressure is imparted from the piston A to the valve assembly. When this pressure overcomes the pressure of the operating uid holding the valve assembly in the position of Fig ure 8, the valve head moves ot of the seat 55 which allows an equalization of pressures around the valve assembly, after which the spring 60 functions to snap the valve assembly to its other position. In such other position valve head 51 engages the seat 54 to shut off ow of operating fluid to passage 35 and at the same time disengages seat 55 to establish communication between passage 35 and the area between piston A and the partition 50. The shifting of the valve engages valve head 52 with the seat 57 and disengages it from seat 56. This movement establishes communication between inlet 33 and the passage 36 to direct operating uid behind the piston B; at the same time communication between the passage 36 and the area between piston B and the partition is shut olf.

Thereafter, the operating uid applied against piston B moves the piston assembly in a direction to the left in Figure 8. During this time a greater effective area is exposed to the operating pressure by the valve head 52 than by the valve head 51 so that the operating pressure maintains the valve in proper position. As the piston B approaches the end of its stroke it engages the disc 51, compresses spring 62 and thereafter applies direct pressure to the valve assembly through an extension 52a provided on the valve head 52. This causes movement of the valve head 52 away from seat 57 allowing equalization of pressures around the valve assembly so that the spring 62 may function to instantaneously snap the valve heads to their original positions as illustrated in Figure 8. This again shifts the pressure in the manner hereinbefore described, and the operation is then repeated.

In the form shown in Figure 8 the power pistons A and B Iare connected through the piston rods `15 with the pump plunger or rod 24 and as the pistons are reciprocated the pump is actuated. In both forms of the invention the control valve which automatically shifts the direction of flow of the operating fluid is mounted wholly within the power cylinder, so that a very compact type of unit is provided. It is evident that as the power pistons approach the end or limit of their respective strokes, the valve mechanism is actuated to instantaneously shift the operating uid and thereby reverse the direction of movement of the power piston assembly.

In a pump apparatus, a cylinder, a power piston assembly reciprocable within the cylinder and comprising spaced pistons, an operating pressure iluid inlet between the pistons, said inlet communicating through a rst passage with one end of the cylinder and communicating with the opposite end of the cylinder through another passage, an exhaust line extending from the cylinder and vin constant communication with the area between the pistons, an annular valve element slidable within the bore of the cylinder to a first position and a second position, said valve element comprising an annular ring portion having a pair of spaced annular flanges, with the space lbetween the anges forming an annular channel, the inlet and passages within the cylinder being so disposed with respect to each other and with relationship to the width of the annular channel that when the valve element is in the rst position communication is established through the channel between the inlet and the rst passage while shutting off communication between the inlet and the second passage, movement of the valve element to its second position shutting olf communication between the inlet and rst passage and simultaneously establishing communication through the annular channel between the inlet and second passage, said valve element being disposed between the pistons and engageable by each of said pistons at the limit of each stroke of the piston assembly, whereby said piston assembly shifts said annular valve element from one position to another, frictional means mounted in the wall of the cylinder and engageable with the ring portion of the valve element for latching said valve element in each of its rst and second positions whereby the resistance of said frictional means must be overcome before said valve element can shift from one position to another, said piston assembly including a piston rod connecting the pistons and said valve element including a spider portion which is slidable on the piston rod, and a coiled spring surrounding the piston rod between each piston and the valve element spider and adapted to be compressed as the piston approaches the valve member, said springs functioning to impart an instantaneous shifting movement to the valve element after the frictional resistance of the frictional means has been overcome.

References Cited in the le of this patent UNITED STATES PATENTS 126,623 Chandler May 14, 1872 955,148 Farnsworth Apr. 19, 1910 1,839,540 Farr Ian. 5, 1932 1,913,308 Hueber et al June 6, 1933 2,092,405 Neveu Sept. 7, 1937 2,098,936 Armstrong et al Nov. 16, 1937 2,555,018 Von Seggern May 19, 1951 FOREIGN PATENTS 325,269 Germany Sept. 11, 1920 63,691 Sweden Sept. 13, 1927 

